Field of the Invention
Aspects of the present disclosure generally relate to an electrophotographic photosensitive member, a process cartridge, an electrophotographic apparatus, and a method for producing the electrophotographic photosensitive member.
Description of the Related Art
In recent years, there have been requirements for electrophotographic apparatuses to be capable of outputting numerous high-quality images (printed products). Therefore, electrophotographic photosensitive members, which can be repeatedly used in electrophotographic apparatuses, are required to have a long lifetime.
To prolong the lifetime of an electrophotographic photosensitive member, it is important to enhance the mechanical strength of the electrophotographic photosensitive member.
Japanese Patent Application Laid-Open No. 2000-066425 discusses a technique that causes a cured product obtained by chain polymerization reaction of a charge transporting compound having a chain-polymerizable functional group to be contained in a surface layer of an electrophotographic photosensitive member to improve the mechanical strength of the electrophotographic photosensitive member, thus attaining the prolongation of the lifetime of the electrophotographic photosensitive member.
Japanese Patent Application Laid-Open No, 2009-031721 discusses a technique that causes a cured product obtained step-growth polymerization reaction of a guanamine compound to be contained in a surface layer of an electrophotographic photosensitive member to improve the mechanical strength of the electrophotographic photosensitive member, thus attaining the prolongation of the lifetime of the electrophotographic photosensitive member.
Japanese Patent Application Laid-Open No. 2013-008013 discusses a technique that causes a cured product obtained by chain polymerization reaction of a urea compound having a chain-polymerizable functional group to be contained in a surface layer of an electrophotographic photosensitive member to prevent the occurrence of image smearing (image deletion).
Japanese Patent Application Laid-Open No, 2013-008014 and Japanese Patent Application Laid-Open No. 2011-133853 discusses a technique that causes a specific urea compound to be contained in surface layer of an electrophotographic photosensitive member.
However, in the electrophotographic photosensitive members described in Japanese Patent Application Laid-Open No. 2000-066425 and Japanese Patent. Application Laid-Open No. 2013-008013, a chain polymerization reaction tends to be inhibited by oxygen in the air, there is such an issue in production that the cured product needs to be formed in a special environment in which the concentration of oxygen is low.
In the electrophotographic photosensitive member described in Japanese Patent Application Laid-Open. No. 2009-031721, an improvement in the mechanical strength of the electrophotographic photosensitive member with a cured product obtained by using a guanamine compound is attempted by the use of a step-growth polymerization reaction in which the above-mentioned issue in production is resolved.
However, since the surface of the electrophotographic photosensitive member becomes not readily refreshable due to an improvement in mechanical strength, image smearing tends to occur due to the repetitive use in a high temperature and high humidity environment, so that it is difficult to attain both an adequate mechanical strength and the prevention of image smearing at the same time.
Furthermore, the need for long lifetime the market is very high, and there is room for further improvement even in the electrophotographic photosensitive members described in Japanese Patent Application Laid-Open No. 2013-008014 and Japanese Patent Application Laid-Open No, 2011-133853.